This invention relates to automatic laminating apparatus for assembling transformer cores, and, more particularly, it relates to an apparatus for rotatably orienting magnetic steel plates on a horizontal feed conveyer.
Transformer cores are constructed by laminating magnetic steel plates in a frame configuration. In automatic laminating devices used to form transformer cores, a feed conveyor is provided for supplying individual plates to a laminating station at which the plates are stacked to form portions of the frame like core. In order to form the frame configuration, the magnetic steel plates are oriented in angular positions on the feed conveyer so that upon arrival at the laminating station, the individual plates are oriented properly for the portion of the frame-like core in which they are to be laminated. As the result, a rotatable apparatus is used in association with the feed conveyor.
FIG. 8 shows a plan view of a conventional rotating apparatus for plates used in a transformer core laminating apparatus. A plate 2, as represented by the dashed line rectangle, is placed on the upper run of endless belts 1 of a belt-conveyer to be conveyed horizontally in the left-right direction of FIG. 8. A rotatable lifting support 3, shown in solid lines, is disposed over the plate 2 and is capable of rotating the plate 2 to a predetermined angular orientation as shown by the dot/dash line 2A while lifting the plate 2.
FIG. 9 shows a side elevation as seen in the direction of an arrow P in FIG. 8. The rotatable lifting support 3, carried at the bottom of a vertical supporting shaft 5, is provided with a plurality of suction devices 4 made of rubber material. Plates like the plate 2 (not shown in FIG. 9) are placed between the suction devices 4 and the conveying belts 1. The suction devices 4 are connected to a suction source (not shown) by an air conduit (also not shown) provided in the rotatable support 3 and the supporting shaft 5 so as to lift an object on the conveying belts 1 when the suction devices are in fluid communication with the suction source.
FIG. 10 is an end elevation as seen in the direction of an arrow Q in FIG. 8. As in the side elevation of FIG. 9, the suction devices 4 are provided across the full length of the undersurface of the rotatable support 3. Also the combined width of the plurality of parallel conveyer belts 1 is at least equal to the length of the support 3. To accommodate magnetic steel plates used in large capacity transformers, this dimension may be as large as 5 meters. Since such a long plate is conveyed and rotated, the width of an adequate belt-conveyer is conventionally provided by the separated and spaced conveying belts 1.
FIG. 11 shows a end view of the conventional apparatus of FIG. 10 in a condition when the plate 2 is being lifted. The plate 2 is lifted in a horizontal orientation by the suction devices 4. In this state, the rotatable support 3 rotates and turns the plate 2 to a predetermined angular orientation. Then the rotatable support 3 descends to return to the initial position as shown in FIG. 10.
However, the required large size of the rotatable support in the above described conventional apparatus presents a problem. As shown in FIG. 11, in order to lift the plate in a horizontal orientation, the plurality of suction devices 4 must be positioned across the whole surface of the plate to be lifted. The rotatable support 3 is, therefore, made larger than the area of the plate 2 so as to provide an adequate number of suction devices 4 to effect a uniform lifting force over the complete area of the largest plate to be used.
If the rotatable support of the conventional apparatus is made smaller, such as represented by the support 30 in FIG. 12, in the case where the plate 2 is a very thin plate of magnetic steel, both edges of the plate 2, being unsupported, hang down as shown. If the rotatable support 30 rotates in this state, both edges of the plate 2 rub against the conveying belts 1, so that the plate 2 is bent or the conveying belts 1 are damaged.
Because of the above problems, the conventional apparatus usually employs a large rotatable support 3. As mentioned above, some large capacity transformers include magnetic plates having a length as much as 5 meters and further, a width as much as 1 meter. Since the plate should be lifted over the whole surface thereof, the rotatable support requires a very large area to provide the suction devices. However, when the rotatable support 3 is of such a large size, a rotating inertia increases and further, the overall weight of the apparatus is increased greatly.